Alloy



Reiuued Jan; 25, 1938 UNITED STATES PATENT OFFICE I ALLOY Robert H.Leach, Fairfleld, =onn.,

assignor to Handy a Harman, New York, N. Y., a corporation of New'Yol-k;

No Drawing. Original No. 2,019,984, dated November 5, 1935, Serial No.29, 1934. Application for 746,273, September reissue December 8,

1937, Serial No. 178,007

6 Claim.

This invention relates to alloys used for soldering and (analogouspurposes, and is concerned more particularly with a novel alloy whichhas relatively low melting and flow-points, and can be used without fluxor with less flux than would otherwise be required Ior producingexcellent joints.

The new alloy includes silver, copper, zinc and phosphorus, and may forsome purposes also include cadmium. The use oi zinc and cadmium incombination produces a more ductile alloy than is obtainable byemploying either metal alone, although in some instances it maybe:desirable to omit the cadmium. Accordingly, by using no cadmium or byvarying the amount of cadmium, examples of the new alloy diil'ering inphysical properties may be obtained to suit particular needs. Thepresence of zinc or cadmium or' both these metals aflects the meltingpoint of the alloy, and in general the higher the proportion of zinc, orcadmium, or both, the lower is the melting point. There is a limit,however, to the extent to which these metals can be employed, whilestill obtaining an alloy suitable for brazing purposes and giving highstrength joints, and I have io'und that it is not desirable to use anaggregate amount greater than aboutv 40% and for most purposes, a lessamount is to be preferred.

The incorporation oi phosphorus in the alloy serves a number ofpurposes. The phosphorus prevents oxidation and permits use of the alloywithout a flux or with less flux than would otherwise be required. Inaddition, it lowers the melting point of the alloy, and improvesits'flowing properties, so that it enters crevices and seams andproduces joints of high tensile strength.

In general, the new alloy consists of the following constituents in theapproximate proportions given:

Per cent Silver 30 to 70 Copper 19 to 35 Phosphorus 0.5 to

' Zinc to 40 In the above analysis, it is to be understood that cadmiummay be substituted wholly or in part for the zinc. When both zinc andcadmium are present, the amount of zinc should preferably be within therange of 10% to 30%, approximately, and the amount of cadmium within therange oi 1% to 20%, approximately.

Specific examples of the new alloy may be given as follows, theproportions being app ox mate.

Of the specific examples the alloy having the composition of Example No.1 has a melting point 01' 1200 F. and a flow point of 1245 F., but itcadmium is added for an equivalent amount of zinc, the melting and flowpoints will be 1100 F. and 1108 F., respectively. The alloy in ExampleNo. 2 has a melting point of 1130 F. and a flow point of 1195 F. and thealloy in Example No. 3 has a melting point of 1340 F. and a flow pointof 1385 F. In alloys containing over 50% silver and no cadmium, themelting and flow points increase with the percentage of silver, butthere is greater ductility and these factors would control the selectionof the most desirable composition for a specific application.

What I claim is:

1. An alloy for soldering and 'simiiar'p'urposes which consists ofsilver ranging from about 30% to about 70%, copper ranging from about19% to about 35%, phosphorus ranging from about Example No. 1 Per centSilver 30 Copper 30 Zinc 38 Phosphorus. 2

Example No. 2 g Per cent .Silver ;.t...i 50 Copper i 27 Zinc 1 22Phosphorus 1 Example No. 3

' Per cent Silver '70 Copper... 1 18 Zinc 10 Phosphorus a 1 0.5% toabout 5%, and zinc ranging from about 10% to about 40%.

2. An alloy for soldering and similar purposes which consists of silverranging from about 30% to about 50%, copper ranging from about 19% toabout 35%, nc ranging from about 10% to about 40%, and phosphorusranging from about 0.5 v to about 5%.

3. An alloy i'or soldering and similar purposes which consists of about30% silver, about 30% copper, about 38% zinc, and about 2% phosphorus.

4. An alloy for soldering and similar purposes wh ch consists of about50% silver, copper ranging from about 27% to about 34%,, zinc rangingfrom about 16% to about 22% and about 1% hosphorus.

5. An alloy tor soidering-and'similar purposes 5 which consists of about70% silver, about 19% copper, ,about 10% zinc. and about 1% phos phorus.

moss

6: An alloy for soldering and similar purposes which consists of silverranging from about 50% to about 70%, copper ranging from about 19% toabout 35%, zinc ranging from about 10% to about 40%, and phosphorusranging from about 0,57, 5

to about 5%.

. ROBERT E. LEACH.

